Multiplexed fluid control system with pressure transducer feedback

Abstract

A multiplexed hydraulic control system includes a pressure transducer fluidically connected to the multiplexer for sequential or periodic connection to a plurality of channels. The multiplexed hydraulic control system provides hydraulic control flows to a plurality of second stage valves while simultaneously multiplexing the pressure transducer. The pressure transducer may be multiplexed to multiple second stage valves or actuators to provide multiplexed feedback for closed loop control of the second stage valves. The system may be used to split or throttle fuel flow to the nozzles of a combustion chamber in turbine engines.

What is claimed is: 
     
       1. A time multiplexed fluid control system for controlling the positions of multiple valve devices, each valve device having a control chamber, comprising: a fluid multiplexer having a plurality of positions for selectively connecting an input and a plurality of outputs, one of the outputs fluidically connected to the control chamber of each valve device;   a modulating valve in fluid communication with the input, producing a controlled output flow through the input, the position of the fluid multiplexer determining which of the outputs receive the controlled output flow; and   a pressure transducer in fluid communication with the fluid multiplexer and connectable to a plurality of channels thereby, the position of the fluid multiplexer determining which of the channels the pressure transducer is in communication with, the pressure transducer operable to produce a multiplexed feedback signal representative of sensed pressures in the channels.   
     
     
       2. The system of claim 1 wherein a plurality of said valve devices are in fluid communication with channels of the pressure transducer, the multiplexed feedback signal being indicative of the individual positions of said plurality of the valve devices for closed loop control of said plurality of valve devices. 
     
     
       3. The system of claim 2 further comprising a controller selectively matching the multiplexed feedback signal with corresponding demand signals, each demand signal relating to a demanded position for a corresponding valve device, said controller generating a plurality of electrical control signals in response to differences between the multiplexed feedback signal and the demand signals, the electrical control signals commanding the modulating valve to provide controlled output flows which set the demanded positions of the corresponding valve devices. 
     
     
       4. The system of claim 3 further comprising a position detection device in sensory communication with the multiplexer to sense a position thereof, the position detection device outputting said position of the multiplexer to said controller for use therein to determine which of said outputs is connected to the modulating valve and which of said channels is connected to the pressure transducer. 
     
     
       5. The system of claim 4 further comprising means for translating the multiplexer between said plurality of positions in a predetermined selected sequence, whereby the multiplexed fluid control system is time division multiplexed. 
     
     
       6. The system of claim 1 wherein the fluid multiplexer comprises a multiplexing sleeve rotatably disposed within a valve body, the channels and the outputs being disposed in the valve body radially about the sleeve, the modulating valve being a spool valve linearly translatable within the sleeve to produce a plurality of positive and negative fluid power signals. 
     
     
       7. The system of claim 1 wherein the multiplexer includes a second input and a plurality of second outputs for multiplexing the pressure transducer separately from the modulating valve, one channel being in fluid communication with each second output. 
     
     
       8. The system of claim 7 wherein a plurality of the second outputs are fluidically connected to a plurality the valve devices to provide pressure sensed feedback therefrom. 
     
     
       9. The system of claim 1 wherein the pressure transducer is fluidically connected to said input and multiplexed through the outputs on the same time multiplexed basis as the controlled output flows. 
     
     
       10. A time multiplexed fluid control system for controlling the positions of valve devices, each valve device having a control chamber and adapted to control a mechanical variable, comprising: a fluid multiplexer having an input and a plurality of outputs, one output fluidically connected to the control chamber of each valve device;   means, associated with the fluid multiplexer, for producing a controlled output flow through the input and in each of the outputs to individually control the position of each of the valve devices on a time multiplexed basis;   a pressure transducer in fluid communication with the fluid multiplexer, the fluid multiplexer periodically connecting the pressure transducer to a plurality of the valve devices on a time multiplexed basis, the pressure transducer providing a multiplexed feedback signal indicating a sensed pressure associated with said plurality of the valve devices; and   a controller connected to the pressure transducer and the producing means, the controller selectively matching the feedback signal with a demand signal and modifying the controlled output flow in accordance therewith to provide closed loop control of said plurality of the valve devices.   
     
     
       11. The system of claim 10 in which the pressure transducer is fluidically connected to the input and therefore multiplexed through the outputs and fluidically connected to the control chambers on the time multiplexed basis. 
     
     
       12. The system of claim 10 wherein the multiplexing valve further includes a second input and a plurality of second outputs, the pressure transducer connected to the second input, the second input connectable to each of the second outputs whereby the pressure transducer is multiplexed separately from said producing means. 
     
     
       13. The system of claim 10 further including means for translating the fluid multiplexer through a plurality of positions, each position connecting the input to one of the outputs, and further comprising a position feedback device in sensory communication with the fluid multiplexer, the position feedback device indicating to the controller the position of the multiplexing valve. 
     
     
       14. The system of claim 10 wherein the pressure transducer is multiplexed by fluid multiplexer to a plurality of parameters not associated with the valve devices. 
     
     
       15. A time multiplexed hydraulic control system for controlling fluid flow among a plurality of fluid passages comprising the combination of: a plurality of valve devices, each valve device having a fluid inlet and a fluid outlet connected to one of the fluid passages, each valve device having a control chamber;   a hydraulic multiplexer having an input and a plurality of outputs, one of the outputs being connected to the control chamber of each valve device;   a modulating valve associated with the hydraulic multiplexer, for providing a controlled output flow in each of the outputs to individually control the position of each of the valve devices on a time multiplexed basis, whereby the multiplexer and modulating valve are adapted to set a fluid flow rate through each of the valve devices for each fluid passage; and   a pressure transducer fluidically connected to the multiplexer for calculation of the fluid flow rate through the valve devices, the pressure transducer generating a pressure feedback signal to a controller for matching with a flow demand signal, to thereby provide for individual control of the fluid flow rate in the fluid passages.   
     
     
       16. The system as in claim 15 wherein the flow passages are part of a fuel manifold in a gas turbine engine, the flow passages delivering a fuel to a plurality of nozzles individually or in groups for discharge into a combustion chamber for combustion. 
     
     
       17. The system as in claim 15 wherein each valve device is engaged by a spring to have an axial position proportional to pressure in the respective chamber, to thereby permit calculation of valve position and the flow rate through each valve device. 
     
     
       18. The time multiplexed hydraulic control system as in claim 15 wherein the hydraulic multiplexer multiplexes the pressure transducer in a first sequence and the modulating valve in a second sequence, the first sequence being different from the second sequence. 
     
     
       19. A time multiplexed hydraulic control system for controlling fluid flow among a plurality of fluid passages, comprising the combination of: a plurality of valve devices, each valve device associated with one of the fluid passages and having a position for adapting the fluid flow rate in its associated fluid passage, each valve device having a control chamber,   a hydraulic multiplexer having an input and a plurality of outputs, one of the outputs being connected to the control chamber of each valve device,   a modulating valve associated with the multiplexer, for providing a controlled output flow in each of the outputs, for individually controlling the position of each of the valve devices on a time multiplexed basis, whereby the multiplexer and modulating valve are adapted to set a fluid flow rate through each of the valve devices for each flow passage; and   feedback means multiplexed among the valve devices for providing a multiplexed signal indicative of the fluid flow rates through each of the valve devices, said feedback means providing the multiplexed signal to a controller for matching with a demand signal, to thereby control the fluid flow rate through each of the fluid passages.   
     
     
       20. The system as in claim 19 wherein the feedback means comprises a pressure transducer. 
     
     
       21. The time multiplexed hydraulic control system as in claim 20 in which the flow passages are part of a fuel manifold in a gas turbine engine, the flow passages delivering a fuel to a plurality of nozzles individually or in groups for discharge into a combustion chamber. 
     
     
       22. The system as in claim 20 wherein the input is sequentially connected to the outputs in a predetermined sequence whereby the time multiplexed hydraulic control system is time division multiplexed. 
     
     
       23. The time multiplexed hydraulic control system as in claim 19 in which the feedback means is multiplexed by the hydraulic multiplexer to the valve devices.